In many software systems such as the OS/2.TM. Extended Edition 1.0 commercially available from the IBM Corporation, it is conventional to provide a precompiler function with the system. The purpose of the precompiler is to generate a combination of language statements and function calls to set up host data required to process various statements in application programs to be executed with the system. An example of such statements, for example, might be structured query language or SQL statements well known in the art which are high level statements formulated for purposes of accessing a database. It is typical in such systems to provide sets of runtime functions which are not externalized except to the degree that they appear in modified source files after precompilation.
One problem with providing such functions is that they typically are designed to be used specifically by a single language such as the C-Language in the case of the hereinabove-noted OS/2 system. However, application programs typically encountered are written in one of a plurality of languages. Accordingly, the need arose for precompiler developers to be provided with a set of application program interfaces or APIs that they could generate calls to in order to communicate at runtime between a given application and a database manager kernel, for example, wherein these APIs were sufficiently generic in order to be used by various languages. However, the proprietor of the software system typically had a vested interest in protecting the interface to such kernels, wherein it was desired that such APIs serve an additional function as an isolation layer between the given application and the kernel.
Yet additional difficult constraints were imposed upon the highly sought after API system resulting in the failure to provide the much-needed interfaces. In attempting to provide precompiler developers with a runtime interface which would be the target of code generated during precompilation, it was recognized that parameters used by the interface must be simple enough to be employed by a wide variety of host languages such a C, Pascal, COBOL, and FORTRAN among others. Moreover, it was necessary that this runtime interface be flexible enough to allow precompilers to generate code allowing for optimization of certain runtime characteristics, such as storage requirements, execution speed, and the like. Still further compounding the problem in delivering such an interfacing system was the need for the runtime interface to provide for application developers' creation of multi-threaded applications to provide performance or functional benefits not obtainable by single-threaded applications. Still further, a system was needed which was capable of identifying which access program to run when it was called from within an application, even when the application was composed of several modules each of which might have a unique access program.
These and other problems have been solved by the present invention wherein an interfacing system and method is provided for interfacing in computer systems to facilitate intercommunication between a wide variety of application and other software system programs.